The invention generally relates to a method for handling compacted bales of solid waste facilitating the smooth transference of the bales from a baling device located at a transfer station to the balefill site. Particularly, the invention is directed toward the receiving and loading of compacted bales from the baler onto a trailer, maintaining the trailer in a closed condition, and carrying the bales in this closed condition to the point of unloading of the balefill, whereupon unloading and stacking at the balefill is efficiently accomplished. Even more specifically, the invention is directed toward loading and unloading bales comprised of municipal solid waste onto and from a closed dump trailer.
In order to meet society's needs for more orderly and efficient collection and disposal of municipal solid waste, acknowledging that conventional sanitary landfill sites are becoming less acceptable to the general public, and because those landfill sites that are acceptable tend to be further removed from the metropolitan areas where most of the municipal solid waste is generated, more transfer stations are being utilized. In addition because the landfill space is becoming so scarce more efficient utilization of that space via baling of the waste prior to diposal is being employed. Also in situations where transfer stations are not employed the possibility of loose papers and other refuse being scattered and carried away from the landfill by wind or birds has become an issue of concern to local residents. Requiring that the loose refuse be dumped inside an enclosed building and compacted into bales and conveyed in an enclosed trailer to the point of bale stacking is a solution to the blowing and scattering problem.
Baling involves the compressing of municipal solid waste into manageably-sized bales which can then be stacked in a very dense form and covered daily with soil. The so-called "balefill" is a type of sanitary landfill employing environmental safeguards to prevent contamination of surrounding ground water and release of gases. The balefill makes more economic and efficient use of the same amount of acreage as a sanitary landfill in which the waste is dumped and compacted with rollers and then covered with soil.
At the transfer stations, which may be remote to the balefill or at the balefill site, the collection vehicles which pick up the waste from the residences and other waste generation points discharge the loose waste inside a building. The loose waste is fed onto conveyors or into a hopper and them into a baler. Locating the transfer station close to the source of the waste generation enables the collection vehicles and crew to spend more time collecting waste and allows for more efficient transport of larger volumes of waste to the balefill via a transfer truck and trailer requiring only a single driver. In comparison, a typical collection crew consists of two workers and a vehicle of only two and one half times or less the net hauling capacity of a transfer trailer.
It is a related problem to provide for a transfer trailer that encloses the solid waste refuse and meets typical municipal sanitation and health code strictures for handling solid waste refuse. This must also be accomplished while cognizant of the problems of odor, litter, rodents and property value impacts surrounding the transfer station facilities and balefills.
Compacted bales of solid waste refuse should also be sized such that they are capable of being loaded onto and unloaded from a transfer trailer in a simple efficient fashion to avoid spillage, make transport easy, and facilitate the efficient stacking of the bales at the balefill site by means of providing generally uniform bale sizes.
It is a further goal of the industry to efficiently unload a covered trailer truck at the balefill site whereby the bales are quickly made ready for stacking in the balefill.
Although the use of log stackers or forklift vehicles of various types at balefill sites have been used to stack bales, the smooth unloading of the bales from the transfer trailers typically requires that the trailer beds be fitted with sleepers to create a space between the bottom bale and the trailer bed for insertion of a forklift time. Incorporation of sleepers into the trailer bed is not compatible with end loading of the trailers and thus necessitates side loading and unloading of the bales and manipulation of a removable cover or the trailer sides. These limitations result in operational problems and inefficiencies, particularly in wet and winter weather. Some previous attempts have sought to slide bales from a sea container onto the ground at a balefill, but a complete solution to the whole problem of providing a method of loading, transport and unloading has not been found. Smooth bed trailers are preferred for loading the bales from the end. A free-sliding arrangement would enable the bales to be slid into the trailers and slid out of the trailer without the need for removal of the trailer sides or cover, but only removal of the rear enclosure or gate which can be hinged.
Highway weight limitations also impact upon the handling of solid waste bales. Modern high density balers are generally capable of compressing municipal solid waste into bales weighing from about 3000 to 3500 pounds. Thus, it does not take very many bales to reach the allowable legal weight permit on Class 1 and Class 2 roadways. As a result, an efficient method to speed-up trailer turnaround time from the transfer station to the balefill, and back, is necessary.
In meeting the needs of communities and business for the collection, handling and disposal of solid waste, the present invention provides a method overcoming for foregoing problems and satisfying safety and health regulations as well.
The method envisions the handling of a bale size usually created by typical baling equipment having dimensions of roughly about 40 inches high, 61 inches long and 46 inches wide. At this size, pairs of bales may be placed side-by-side in trailer beds having standard outside widths of less than 102 inches. The 102 inch trailer width is the maximum width currently allowed in the United States without special permits. The invention is best suited for use with bales that are made by auto-loading baling devices that tie the bales with wire and incorporate a bale door, which devices achieve uniform, neat and manageable bales made from solid waste.
Another problem encountered in the use of dump trailers is frictional resistance along the bed of the trailer that may be exacerbated by the expanding nature of the compacted bales. Accordingly, it is further a goal of the invention to utilize a slick, lightweight lining for a trailer bed whereby to make the slip angle considerably less than the maximum tilt angle of a dump trailer--usually about 45.degree.--and yet resist abrasion and impact from repeated sliding during loading and unloading of the bales. The lining facilitates the automatic dumping of the bales at the balefill site at a slip angle usually less than half of this full tilt angle even during weather conditions which might otherwise cause bales to freeze or stick together.
The inventive method further provides for the efficient loading of transfer trailers by taking advantage of automatic loading apparatus usually incorporated by manufacturers into their balers and having autoloading rams which may be used to include a step of indexing the bales in pairs for facilitating the direct loading onto the trailers. Preferably, aluminum frameless-type trailers are envisioned, which are approximately 40 feet long and offer a fully loaded 80,000 pound weight capacity for the tractor trailer combination that is spread over five or more axles pursuant to meeting allowable legal weight limits as established by the highway department in the locale where the trailers will be utilized. If the transfer station is located at the balefill, or in close proximity such that limitations are not imposed, the weight, length and width of the trailers may be increased. The auto-loading step provides for indexing pairs of compacted bales usually at either of two or more loading positions, whereby trailers may be arranged at each location. In that way, when one trailer is loaded and then driven away, an empty one may move into its place, while yet another empty trailer--located at another loading position-- may be loaded. Thereby, continuous loading takes place by indexing the bales to a trailer loading location.
The dump trailer may further be provided with a fixed cover for fully covering the baled refuse. A rear swing-door of known design is used to close the end of the trailer. Therefore the method achieves the goal of providing for the transport of refuse in a fully closed condition to meet municipal codes and satisfy health and sanitary concerns. As an additional benefit, due to the end loading and unloading feature, there is no need to remove the trailer top or sides, which is a distinct improvement over the techniques commonly employed by the balefill operators.
At the balefill site, the tilting motion of the trailer drops the bales in sequential pairs onto the ground whereby they may be picked by a log stacker, forklift truck, or the like, for stacking at the balefill.
The auto-loaded bales are arranged side-by-side one bale deep in a sufficient number to meet legal weight limits for a trailer truck. The inventive method allows the transfer trailer to be loaded one bale deep and also arrange the bales at the minimum length on the trailer bed, up to maximum highway weight limits, whereby a shorter trailer may be used. The method is therefore directed toward high density baling systems where municipal solid waste may be compacted in densities of from about 44 to about 61 pounds per cubic foot. If the transfer station is located at the balefill, or such that a private road can be utilized, wider and more heavily loaded trailers may be employed.
In providing for an enclosed trailer environment, a cover made of lightweight aluminum, fiberglass, or other suitable weather resistant material, may be used. The cover can be fixedly attached to securely enclose the trailer. Access to the bales from the top is not necessary. One important benefit of the invention is permitting the use of a lightweight fixed trailer top, which overcomes many difficulties in the past with canvas-type covers or tarpaulins that are unwieldy, difficult to handle in wet and cold weather, and must be tied down during transit. The tarpaulin coverings also deteriorate through repeated use.
The autoloading or sliding of bales into the trailers from the rear requires that the trailer sides be rigid so as to prevent the bales from wandering or becoming canted inside the trailer. The invention satisfies this requirement in that the method envisions using trailer sides that are rigid and lined, yet the trailer top is lightweight and weatherproof.
In further achieving the goal of efficient handling of trailers at a transfer station, the method may optionally include coordinating up to three different type tractors for moving the trailer. In this regard, the usual highway-type tandem axle tractor may be provided to pull a trailer from the balefill to a remote transfer station site and disconnect, whereupon a smaller tractor, called a trailer spotter, may take the detached trailer and move it to the loading position at a baling device. This is optional. When loaded, the trailer spotter will take the trailer to a parking area and disconnect, whereupon a tandem axle tractor will again be attached to the trailer for transporting it to the balefill site. Alternatively, the highway-type tandem axle tractor may attach to the loaded trailer while it is mated to the baler, whereupon the tractor would pull forward, stop, close the tailgate and then proceed directly to the balefill for unloading. At the balefill site, the loaded trailer will be unloaded at the point of balefill filling, or at a nearby location it will be detached from the tandem axle tractor and a special heavy-duty all-terrain tractor vehicle, equipped with a heavy-duty suspension system, axles, tires, brakes and hydraulic pump system, will be attached for traversing the uneven ground usually found at a balefill. The all-terrain tractor will pull the trailer to the active face of the balefill and activate the hydraulic system of the dump trailer to tilt it and slide off the bales. In the meantime, the just-detached tandem axle tractor will hitch to an empty trailer at the balefill and return to the transfer station for another load of bales. A trailer thereby goes through this sequence repetitively.